Circuit breaker

ABSTRACT

A circuit breaker wherein electrical arrangement for detecting excess current in and switching or breaking power supply contacts for associated circuit and mechanical arrangement for transmitting ON-OFF operation or contact switching operation to the contacts are separately disposed as electrically insulated by a separation wall in a chassis for integrally housing the both arrangements. The separation wall has only two narrow apertures for allowing the motion responsive to detected excess current transmitted to the mechanical arrangement and therethrough back to the contacts.

United States Patent [191 Yoshino et al.

CIRCUIT BREAKER Inventors: Akira Yoshino; Hitoshi Imanishi,

both of Seto, Japan Matsushita Electric Works, Ltd., Osaka, Japan Filed:Apr. 3, 1974 Appl. No.: 457,423

Assignee:

Foreign Application Priority Data Apr. 5, 1973 Japan 48-38934 Apr. 6,1973 Japan 48-39932 US. Cl. 335/6; 335/201; 335/202; 337/46 Int. Cl.H0lh 9/34 Field of Search 335/6, 202, 201, 190, 143; 337/46, 53, 23, 143

References Cited UNITED STATES PATENTS 6/1948 Wise 335/143 June 10, 19752,540,491 2/1951 Rowe et al. 335/23 2,660,642 11/1953 Warren 337/532,703,350 3/1955 Rosing 337/46 2,989,604 6/1961 Wegh 335/6 3,240,9043/1966 Dowdle et al 337/46 Primary Examiner-J-larold Broome Attorney,Agent, or F irm-Wolfe, Hubbard, Leydig, Voit & Osann, Ltd.

[ 5 7 ABSTRACT A circuit breaker wherein electrical arrangement fordetecting excess current in and switching or breaking power supplycontacts for associated circuit and mechanical arrangement fortransmitting ON-OFF operation or contact switching operation to thecontacts are separately disposed as electrically insulated by aseparation wall in a chassis for integrally housing the botharrangements. The separation wall has only two narrow apertures forallowing the motion responsive to detected excess current transmitted tothe mechanical arrangement and therethrough back to the contacts.

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IZQ lh ,9\ 1 Fig. 24C 22a 22 [2a Ih CIRCUIT BREAKER This inventionrelates to a circuit breaker for protecting a load by breaking a circuitin case such excess current as a short-circuiting current or overloadcurrent flows through the circuit.

Generally a circuit breaker is formed largely of three parts of anoperating part, switching contact part and excess current detecting partso that, in case an excess current flows through a circuit, this excesscurrent will be detected by the excess current detecting part and theswitching contact part will be operated, through the operating part, bythis detection to switch off the circuit. The above mentioned threeparts have been arranged and fixed on the same surface (for example, theupper surface) of a chassis made of a synthetic resin. However, theoperating part is mostly of a mechanical formation while the switchingcontact part and excess current operated element are mostly of electricformations. Therefore, there have been defects that, when they are fixedas arranged on the same surface of the chassis, the assembling workspecifically in the mechanical field must be carried out with a largerattention than is required to the electric parts outside the mechanicalfield and is, therefore, inefficient and that, in the case of themaintenance and inspection, the mechanical part and electrical part cannot be checked separately from each other and the whole parts must bechecked.

Further, many of metal parts are used for the operating part and,therefore, it must be considered to insulate this operating part fromboth of the switching contact part and excess current detecting partwhich are electrical parts.

In the present invention, in view of the above mentioned points, apartition wall is integrally formed in the middle on the inside surfaceof the side wall of a case made of a synthetic resin to separately formupper and lower space parts which are open respectively outward, ahandle operating part is arranged in the upper space part, a switchingcontact part and excess current detecting part are arranged in the lowerspace part, holes are made vertically through both sides of thepartition wall, a moving plate for operatively connecting the handleoperating part and switching contact part with each other is arranged inthe hole on one side and an operatively connecting plate for operativelyconnecting the excess current detecting part and handle operating partwith each other is arranged in the hole on the other side so that suchdefects as referred to before will be successfully solved.

An object of the present invention is, therefore, to provide a mold casecircuit breaker wherein each of the said parts which are respectivelymade to be a unit can be arranged in an optimum state and the assemblingwork and maintenance service can be carried out efficiently.

Other objects and advantages of the present invention will be made clearby the following description of the invention detailed with reference toa preferred embodiment in conjunction with accompanying drawings, inwhich:

FIG. I is an explanatory view showing schematically the arrangement of acircuit breaker of the present invention;

FIG. 2 is an upper surface view of the apparatus of the presentinvention;

FIG. 3 is a lower surface view of the same with a back lid removed;

FIG. 4 is a side view of the same;

FIG. 5 is a view showing the interior with a part of a cover cut off;

FIG. 6 is an upper surface view shown with the cover removed;

FIG. 7 is an upper surface view in FIG. 6 shown with an upper lidremoved;

FIG. 8 is a lower surface view in FIG. 3 with a lower lid removed;

FIG. 9 is a sectioned view shown along an input terminal and outputterminal in FIG. 6;

FIGS. 10A through 10C are upper surface view, lower surface view andvertical sectioned view substantially at the centre of a chassis;

FIG. 11 is a cross sectional view along a carrier of the chassis;

FIG. 12 is a perspective view of an operating part;

FIG. 13A is a perspective view of the operating part as disassembled,and FIG. 138 shows main elements in the operating part;

FIG. 14A is a front view of the operating part as assembled;

FIG. 14B is a rear view of the same;

FIG. 14C is a side view of the same;

FIG. 15 is a perspective view of an electromagnet employed in thedevice;

FIGS. 16A through 16C show a coil in the above;

FIG. 17 is a perspective view of a switching contact unit;

FIG. 18 is a perspective view of a carrier;

FIG. 19 is a perspective view of an armature;

FIG. 20 is an elevation of a handle;

FIGS. 21 and 22 are fragmentary sectioned views for explaining theoperating part as fitted;

FIGS. 23A, B and C are views for explaining the operation of theoperating part;

FIGS. 24A through 24C are view for explaining the operation of thecontact plate;

FIGS. 24A through 24C are fragmentary sectioned views showing operationsof contacting plate; and

FIGS. 25A and 25B are explanatory views showing operative relationbetween certain main elements in the operating part.

FIG. 1 shall be explained in the following.

FIG. 1 shows a unit arrangement of a circuit breaker of the presentinvention. In the drawing, INPUT is an input terminal, OUTPUT is anoutput terminal and these terminals are arranged on both sides of a caseA. B is a switching terminal. C is an excess current detecting part. Dis an operating part. An upper space and lower space are formed by apartition wall E in the case A. The operating part D is arranged in theupper space. The switching contact part B and excess current detectingpart C are arranged in the lower space. F is an operatively connectingplate integrally having an armature for transmitting the operation ofthe excess current detecting part C to the operating part D. F is acarrier for transmitting the operation of the operating part to theswitching contact .part. The electric current path is from the inputterminal through the switching contact part B and excess currentdetecting part C to the output terminal OUTPUT. The operation sequenceis from the excess current detecting part C through the operativelyconnecting plate F, operating part D and carrier F to the switchingcontact part B. G is a handle. The operat- 3 ing part D is manuallyoperated by the handle G so as to make ON and OFF.

FIG. 2 shows an upper surface view, in which 57 is a handle to berotated so as to have three positions of U, V and W within a fan-shapedconcave part 68 provided on a cover 65. The trip is indicated by a redmark appearing in an indicating window hole 62 made on the upper surfaceof the case. 70 is a set screw used to fit the cover 65 to the chassis.

FIG. 3 is a lower surface view showing the circuit breaker of thepresent invention with the bottom plate removed. Thin parts 69 areprovided on the side wall 65a of the cover 65 so that electric wires 66may be inserted and fitted within the unit by removing said parts. I isa chassis, and 64 is its lower lid.

FIG. 4 shows a side view of the circuit breaker. A handle 57 isrotatably provided on the cover 65. 69 is a thin part.

FIG. 5 shows a vertically sectioned view of the above. The electricwires 66 are fitted to the chassis 1.

FIG. 6 is an upper surface view of the device in FIG. 1 shown with thecover 65 removed. 5 and 6 are respectively an input terminal and outputterminal. A fanshaped indicating plate 63 is fixed integrally with thehandle 57 to the lower part of the handle 57. A trip indicating part 63ais provided on this indicating plate so that, with the rotation of thehandle 57, the trip indicating part 63a will move and that, when theindicating part 63a is positioned below the indicating window hole 62 ofthe lid 59, the trip state will be indicated. 59b is a concave part madeon the upper lid 59. 59C is an edge of the lid.

FIG. 7 is a view showing the interior of the device shown in FIG. 6 withthe upper lid 59 removed.

In the drawing, the operating part D is secured between both side walls2 of the chassis I. There are shown a carrier F (indicated by 22 in thedrawing) operated by said operating part D and an operatively connectingplate F (indicated by 25 in the drawing) operated by the excess currentdetecting part C.

FIG. 8 is a view shown in FIG. 3 with the lower lid 64 removed. Thereare shown the excess current detecting part C, switching contact part Band operatively connecting plate F (25) operated by the excess currentdetecting part C.

FIG. 9 is a vertically sectioned view of the device of the presentinvention and is a detailed view corresponding to FIG. 1. There areshown the input terminal a 5, switching contact part B, excess currentdetecting part C, operatively connecting plate F, operating part D,carrier F and output terminal b 6. The excess current detecting part Cand operating part D are arranged as separated above and below thepartition wall E(3) of the case.

FIGS. 10A through 10C show a chassis A(1), wherein FIG. 10A is an uppersurface view thereof. The operating part D (not illustrated here) isfitted in the space between the side walls 2. 71 is a hole for fittingthe operating part D. The space is sectioned into an upper space andlower space by a partition wall 3. 72

and 73 are communicating windows made in the.partition wall for housingthe elements forming the excess current detecting part C as describedlater. FIG. 10C shows a vertically sectioned view of the chassis. Thereare shown the partition wall 3 and communicating windows 72 and 73.

FIG. 11 is a sectioned view of the device along the communicating window72, wherein the carrier 22 (or F) is shown here.

Now the formation of each part shall be detailed.

FIG. 12 shows an operating part unit. FIG. 13A shows the respectiveelements thereof as disassembled in a perspective view. The abovedescribed operating part D is held between two ground plates 33 and 33'.39 is an arcuate groove made in the ground plates. is a hole made ineach ground plate, in which the long leg 37a of a later describedU-shaped shaft 37 is pivoted. Said U-shaped shaft 37 has a long leg 37aand short leg 37b. In an operating plate 38 formed to be U- shaped bybending two plates, there are formed two holed 38a and 38b and a calkedpin 38c inside. The long leg 37a of the shaft 37 is inserted through thehole 38a of the operating piece 38 and is inserted into the hole 75 ofthe ground plate 33. The short leg 37b is inserted into the hole 38b ofthe operating piece through a roller 76 contained inside the operatingpiece 38 (see FIG. 12). That is, the operating piece 38 is fitted to theground plates 33 and 33 so as to be rotatable with the shaft 37a as acenter. 40 is a turning arm provided with a tip part 40a as somewhatinclined at one end, with a hole 400 at the other end and with aprojection 40b in the substantially intermediate part. A shaft 41 is inserted in the hole 40c of the turning arm 40. Further, the turning arm40 is inserted in the intermediate part (between the hole 406 andprojection 40b) into the intermediate part (between the hole 38b and pin38c) of the operating plate 38 (see FIG. 12B). 42 is a hanging framebent to be a U-shaped. 42a is its connecting part. 42b is a pivotinghole. The hanging frame 42 has at its tip engaging parts 44 with whichthe shaft 41 of the turning arm 40 is to be engaged and inclined parts45. The ground plates 33 and 33 are combined with each other with afixed space between them by inserting the projections at both ends ofcalked rivets 34 into the holes 33a and 33 'a. The operating plate 38 isrotatably supported between both ground plates with the long leg 37a ofthe U-shaped shaft 37 inserted in the holes 75 of the ground plates 33and 33'. The hanging frame 42 is rotatably supported by the groundplates with a shaft 43 inserted in the hole 42b of the hanging frame andthe holes 33b and 33'b of the ground plates. 49 is a responding pieceformed to be substantially L-shaped and having a bent part 49b formed atone end, a pivoting hole 49c formed at the other end a projection 52formed on the sideopposite the bent part 49b. The responding piece 49 isrotatably supported between the ground plates 33 and 33 by inserting ashaft 50 in the hole 490 of the responding piece 49 and the respectiveholes 330 and 33 'c of the ground plates 33 and 33.

The above mentioned responding piece, hanging frame and turning arm areso arranged that, as shown in FIG. 13B, the tip parts 49a and 52 of theresponding piece 49 will be engageable with the bent part 42a of thehanging frame 42 and the shaft 41 inserted in the hole 40c of theturning arm 40 will be contactable with the engaging part 44 andinclined part 45 of the hanging frame 42. A spring 51 is insertedbetween the projection 54 of the responding piece 49 and the bentprojection 53 of the ground plate 33 so as to give a counter-clockwisepressing force to the responding piece 49. A spring 56 is engaged at oneend with the short leg 37b of the U-shaped shaft 37 and at the other endwith the hole 33d of the ground plate 33 so as to give a clockwisetorque to the operating plate 38. 46 is a U- shaped spring inserted atthe open end 46b in the holes 48 of the ground plates 33 and 33',engaged in the intermediate part 46a with the cut and raised parts 47 ofthe ground plates 33 and 33 and contacted at the other end 46c with thesides 44d of the engaging parts 44 so as to give a clockwise torque tothe engaging parts 44. The thus formed state is shown in FIGS. 14Athrough 14C, in which FIG. 14A shows a front view of the operating part,FIG. 148 shows its rear view and FIG. 14C shows its side view.

FIGS. 15 and 16A through 16C show an oil dash pot type electromagneticdevice employed as an excess current detecting part. It is formed of acoil 17, coil frame 18, L-shaped yoke and oil dash pot 20.

FIG. 17 shows a switching contact unit, in which a movable contact 13 isprovided at the tip of a contact plate 12, a hole 12a is provided in theintermediate part, a middle leg 10a of an E-shaped supporting metalpiece 10 is inserted in the hole 12a, the contact plate 12 is embracedon the sides by hooked parts provided at the tips of both legs 10b and100 and the contact plate 12 is supported rotatably on the supportingmetal piece 10 by a coil spring 77 fitted on the middle leg 10a. 78 is aterminal metal piece connected with the contact plate 12 through a leadwire 15.

FIG. 18 shows the carrier 22 (or F) in which grooves 22a for insertingthe contact plate 12 are made on the lower side and a stepped part 24 tocontact the turning arm 40 is made on the upper side as described later.

FIG. 19 is of an operatively connecting plate to which is fixed anarmature 25 formed of a turning plate 27, to the lower side of which isfixed an iron piece 26 with a pin 29 and in a part of which is provideda projection 25 to push the bent part 49b of the responding piece 49. 30is a supporting shaft provided to project at each end of the operativelyconnecting plate so as to rotatably fit the plate to the chassis l asdescribed later.

FIGS. 20 and 22 show the handle 57 made of a synthetic resin. 57a is ahole in which the long leg 37a of the U-shaped shaft 37 is to beinserted and which is made through the handle 57. 57b is a hole in whichthe short leg 37b is to be inserted and which does not pass through thesurface.

Now the assembly of the device of the present invention shall beexplained.

The respective leg parts 5b and 6b of the L-shaped input terminal metalpiece 5 and output terminal metal piece 6 are inserted respectively inthe concave parts la and 1b of the chassis I (see FIGS. 7, 8, 9 and 10)made of an insulator. Wire fastening screws 7 are fitted to therespective upper pieces 50 and 6a of the terminal metal pieces 5 and 6and a fixed contact 9 is provided on the leg part 5b of the inputterminal metal piece 5.

Then, the opening on the back surface of the chassis (FIG. 10B) isdirected upward andthe stepped part.24 of the carrier 22 (FIG. 18) isinserted in the communicating window 72 of the chassis I, then thesupporting metal piece 10 (FIG. 17) of the contact plate 12 is insertedin the concave part 1d (FIG. 10B) of the chassis and the metal piece 78is inserted in the groove 1c of the chassis to fit the contact plate.Then the coil frame 6 18 of the electromagnet (FIGS. 15 and 16) isinserted between the wall parts 1 f and lg of the chassis to fit theelectromagnet, and the coil 17 is soldered in the end part 17a to themetal pieces 78 and 66. Then the back lid 64 is secured to the bottomsurface of the chassis.

Thus the assembly of the electric parts through the opening on the backsurface of the chassis is completed. Then the opening on the frontsurface of the chassis is (FIG. 10A) is directed upward. First, the hole71 is aligned with the hole 33 of the ground plate of the completedoperating part (FIGS. 12 and 14) and the operating part is fixed to thechassis with the rivet 36 (FIG. 21). Then the operatively connectingplate 25 is fitted. The indicating plate 63 indicating the trip isfitted to the U-shaped shaft 37, then the upper lid 59 is secured to theupper surface of the chassis l, the long legs 37a and 37b of theU-shaped shaft 37 are inserted respectively in the holes 57a and 57b(FIG. 20) of the handle 57, a lock washer 57b is fitted to the upperpart of the long leg'37a, a lid 79 is fixed above the long leg 37a (FIG.22) and a case 65 is applied (FIGS. 3 and 4).

Now the operation of the device according to the present invention shallbe described in the following.

i. FIG. 23A shows the contact in the OFF-state in which the contactplate 12 is separated from the fixed contact 9 (see FIG. 24A). In thiscase, the handle 57 is in the position of W in FIG. 2 and the indicatingplate 63 is in the position of W in FIG. 6. In this case, the projection52 of the responding piece 49 is engaged with the end part 42b of thehanging frame 42 and the shaft 41 of the turning arm 40 is positioned atthe left end of the arcuate groove 39 of the ground plates 33 and 33'and is engaged with the inclined part 44b of the hanging frame 42.

ii. When the handle 57 is rotated counterclockwise so as to be in thestate shown in FIG. 233 (the handle position is in the state of U inFIG. 2), the handle will rotate with the shaft 37a as a center, theoperating plate 38 will also rotate together with the handle, and theupper end part 40a of the turning arm 40 will rotate clockwise with theshaft 41 as a center. Therefore, the carrier 22 will move rightwardagainst the resiliency of the spring 14 and, at the same time, thecontact will move toward ON against the resiliency of the spring. Atthis time, in case the roller (of the roller bearing) slides while underthe reaction on the projection provided on the turning arm and passesthe apex of the projection, the displacement of the operating plate willbecome maximum. When the U-shaped arm 37 further rotates and the rollerlowers down the slope of the projection, the carrier 22 will somewhatreturn to the OFF side. In this state, the spring 56 to return thehandle will give a force to move the turning arm to the OFF side but, byovercoming it, a stable state will be made and the ON state will beobtained, because a dead point is formed at the projection 4b of theturning arm.

iii. If an excess current flows in this state (see FIG. 9), theattracting iron core 19 of the electromagnet will attract the armature25 and the contact will be OFF so as to be in the trip state. Itsdetails are as follows.

Now, by the resiliency of the spring 14, the. carrier 22 will be pushedtoward OFF side and this force will give a clockwise torque component tothe slope 44b of the hanging frame 42 through the turning arm and to thehanging frame 42 through the shaft 41 of the turning arm and will give atorque. When the responding piece 49 and the frame are disengaged fromeach other, the

1. A circuit breaker comprising an input terminal part, a switchingcontact part electrically connected with said input terminal part, anexcess current detecting part electrically connected with said switchingcontact part, an output terminal part electrically connected with saidexcess current detecting part, an operating part for operating saidswitching contact part in response to an electric output of said excesscurrent detecting part, means for converting said electric output of theexcess current detecting part into a mechanical motion to transmit saidmotion to said operating part, means for transmitting motions of theoperating part to the switching contact part, and a chassis made of anelectrically insulative material for housing all said parts andelements, said housing chassis comprising a main body having anintermediate partition wall defining on opposite sides thereof separatedfirst and second chambers which are open in opposing directions withrespect to said partition wall, said partition wall being provided witha pair of small apertures to permit communication between said first andsecond chambers, and lid members for closing the opening of said firstand second chambers, said switching contact part and excess currentdetecting part being housed in said first chamber and operatively fixedto one surface of said partition wall, said operating part being housedin said second chamber and operatively fixed to the other surface of thepartition wall, said converting means extending through one of said pairof apertures in the partition wall to operatively couple the excesscurrent detecting part with the operating part, and said transmittingmeans extending through the other aperture to operatively couple theoperating part with the switching contact part.
 2. A circuit breakeraccording to claim 1 wherein said partition wall of the chassis isprovided at said first chamber side with recesses adapted to receivesaid excess current detecting part and said switching contact part.
 3. Acircuit breaker according to claim 1 wherein said switching contact partis formed of at least a contact plate having a movable contact at thetip and a window in the part near the other end and an E-shapedsupporting metal piece, the middle leg of said supporting metal piece isinserted in the window of said contact plate and the tip parts of bothside legs of said supporting metal piece embrace said contact platewhich is pressed against the embracing parts of both legs of thesupporting metal piece by a spring fitted to said middle leg.
 4. Acircuit breaker according to claim 3 wherein a portion of saidtransmitting means extends into said first chamber and forms at leastone opening to loosely fit therein said contact plate of the switchingcontact part.